Telescopic or other extendable structures are provided for telephone apparatuses in order to make the device physically small in a transport position and to bring the loudspeaker and microphone thereof close enough to the ear and mouth respectively of a human user in an operational position. FIGS. 1 to 5b illustrate some prior art structures of this kind. The mobile telephone 100 of FIG. 1 comprises a body part 101 and a microphone arm 102 which is rotatably mounted to one corner of the body part. In the operational position shown in FIG. 1 the distance between the loudspeaker 103 at the top of the body part and the microphone 104 at the distant end of the microphone arm approximates the distance between the ear and mouth of a typical human user. The mobile telephone 200 of FIG. 2 comprises a body part 201 and a hinged flip cover 202 which in a transport position covers a keypad 203 and in the operational position shown in FIG. 2 brings the microphone 204 at the distant end thereof far enough from a loudspeaker 205 in the body part. The mobile telephone 300 in FIG. 3 resembles functionally that 200 of FIG. 2, but the cover part 302 slides on a pair of sliding rails with respect to the body part 301 instead of rotating around a hinge. Keypad 303, microphone 304 and loudspeaker 305 serve same functions as in FIG. 2.
FIG. 4 illustrates a mobile telephone 400 which comprises a lower body part 401 and an upper body part 402. The latter houses a loudspeaker 403, a display 404 and a limited number of keys in a quickfire keypad 405. The lower part houses a full (alpha)numerical keypad 406, a microphone 407 and an antenna 408. An exemplary structure of this kind is known e.g. from the Finnish registrated design application number 285/97. FIGS. 5a and 5b illustrate another known telescopic structure for a mobile telephone which differs from that of FIG. 4 in the mutual arrangement of the functional components. The telephone consists of an upper part 501 and a lower part of which the upper part houses an integral antenna 503, a radio transceiver 504, a loudspeaker 505, a display 506, a smart card reader 507 and a small keypad 508. The lower part comprises an extended keypad 509, a battery pack 510 and a charging connector 512 for coupling the telephone to a battery charger (not shown). The microphone 511 is located in the upper part, but it could also be in the lower part. The structure of FIGS. 5a and 5b is known e.g. from the European patent publication number EP 0 944 219.
A still further prior art extendable structure for a portable telephone is known from the European patent publication number EP 0414 365. The structure comprises a housing having a main body and an extending sleeve-like portion mounted for longitudinal slidable movement between a retracted position when not in use and an extended position for use. In a preferred arrangement, the earphone is present in the main body and the microphone is in the extending portion. The telephone includes a plurality of buttons or keys which can be selectively actuated for operating the telephone. In one embodiment the extending portion is adapted to conceal selected ones of the buttons or keys when it is in the closed position to prevent accidental actuation of these buttons or keys.
There are various disadvantages associated with the known extendable telephone structures. In many cases the limited thickness of the extendable parts gives a shaky appearance to the structure in the extended configuration. Bringing the parts from the retracted configuration to the extended configuration is often somewhat complicated and requires the use of two hands. Electrical connections between the structural entities often necessitate the use of visible conductors: for example the structure of FIG. 3 comprises a pair of exposed conductor tracks at the lower side of the sliding cover 302. The visibility of electrical conductors tends to irritate users, because uninformed people are afraid of getting electric shocks.